11
F
ORWARDING
D
ATABASE
C
OMMANDS
The layer 2 forwarding database commands in the Command Line Interface (CLI) are listed (along with the appropriate parameters) in the following table.
Command Parameters create fdb create multicast_fdb
<vlan_name 32> <macaddr> port <port>
<vlan_name 32> <macaddr> config multicast_fdb config fdb aging_time delete fdb clear fdb show multicast_fdb show fdb config multicast port_filtering_mode show multicast port_filtering_mode
<vlan_name 32> <macaddr> [add | delete] <portlist>
<sec 10-1000000>
<vlan_name 32> <macaddr>
[vlan <vlan_name 32> | port <port> | all]
{vlan <vlan_name 32> | mac_address <macaddr>}
{port <port> | vlan <vlan_name 32> | mac_address
<macaddr> | static | aging_time}
[<portlist> | all] [forward_all_groups | forward_unregistered_groups | filter_unregistered_groups]
{<portlist>}
Each command is listed, in detail, in the following sections.
create fdb
Purpose Used to create a static entry to the unicast MAC address forwarding table (database)
Syntax
Parameters create fdb <vlan_name 32> <macaddr> port <port> command address forwarding database.
<vlan_name 32> address resides.
− The name of the VLAN on which the MAC
Restrictions
<macaddr> − The MAC address that will be added to the forwarding table.
<port> − The port number corresponding to the MAC destination address. The switch will always forward traffic to the specified device through this port.
Only administrator-level users can issue this command.
Example usage:
To create a unicast MAC FDB entry:
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DES-3550:4#create fdb default 00-00-00-00-01-02 port 5
Command: create fdb default 00-00-00-00-01-02 port 5
Success.
DES-3550:4#
create multicast_fdb
Purpose Used to create a static entry to the multicast MAC address forwarding table (database)
Syntax
Description
Parameters
Restrictions create multicast_fdb <vlan_name 32> <macaddr>
This command will make an entry into the switch’s multicast MAC address forwarding database.
<vlan_name 32> − The name of the VLAN on which the MAC address resides.
<macaddr> − The MAC address that will be added to the forwarding table.
Only administrator-level users can issue this command.
Example usage:
To create multicast MAC forwarding:
DES-3550:4#create multicast_fdb default 01-00-00-00-00-01
Command: create multicast_fdb default 01-00-00-00-00-01
Success.
DES-3550:4#
config multicast_fdb
Purpose Used to configure the switch’s multicast MAC address forwarding database.
Syntax
Description
Parameters config multicast_fdb <vlan_name 32> <macaddr> [add | delete]
<portlist>
This command configures the multicast MAC address forwarding table.
<vlan_name 32> − The name of the VLAN on which the MAC address resides.
<macaddr> − The MAC address that will be added to the multicast forwarding table.
[add | delete] − Add will add ports to the forwarding table. Delete will remove ports from the multicast forwarding table.
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config multicast_fdb
<portlist> − Specifies a range of ports to be configured.
Restrictions
Only administrator-level users can issue this command.
Example usage:
To add multicast MAC forwarding:
DES-3550:4#config multicast_fdb default 01-00-00-00-00-01 add
1-5
Command: config multicast_fdb default 01-00-00-00-00-01 add 1-
1-5
Success.
DES-3550:4#
config fdb aging_time
Purpose Used to set the aging time of the forwarding database.
Syntax
Description
Parameters
Restrictions config fdb aging_time <sec 10-1000000>
The aging time affects the learning process of the switch. Dynamic forwarding table entries, which are made up of the source MAC addresses and their associated port numbers, are deleted from the table if they are not accessed within the aging time. The aging time can be from 10 to 1000000 seconds with a default value of 300 seconds. A very long aging time can result in dynamic forwarding table entries that are out-of-date or no longer exist. This may cause incorrect packet forwarding decisions by the switch. If the aging time is too short however, many entries may be aged out too soon. This will result in a high percentage of received packets whose source addresses cannot be found in the forwarding table, in which case the switch will broadcast the packet to all ports, negating many of the benefits of having a switch.
<sec> − The aging time for the MAC address forwarding database value. The value in seconds may be between 10 and 1000000 seconds.
Only administrator-level users can issue this command.
Example usage:
To set the fdb aging time:
DES-3550:4#config fdb aging_time 300
Command: config fdb aging_time 300
Success.
DES-3550:4#
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delete fdb
Purpose
Syntax
Description
Parameters
Used to delete an entry to the switch’s forwarding database. delete fdb <vlan_name 32> <macaddr>
This command is used to delete a previous entry to the switch’s
MAC address forwarding database.
<vlan_name 32> − The name of the VLAN on which the MAC address resides.
<macaddr> − The MAC address that will be added to the forwarding table.
Only administrator-level users can issue this command. Restrictions
Example usage:
To delete a permanent FDB entry:
DES-3550:4#delete fdb default 00-00-00-00-01-02
Command: delete fdb default 00-00-00-00-01-02
Success.
DES-3550:4#
Example usage:
To delete a multicast fdb entry:
DES-3550:4#delete fdb default 01-00-00-00-01-02
Command: delete fdb default 01-00-00-00-01-02
Success.
DES-3550:4#
clear fdb
Purpose
Syntax
Description
Parameters
Used to clear the switch’s forwarding database of all dynamically learned MAC addresses. clear fdb [vlan <vlan_name 32> | port <port> | all]
This command is used to clear dynamically learned entries to the switch’s forwarding database.
<vlan_name 32> − The name of the VLAN on which the MAC address resides.
<port> − The port number corresponding to the MAC destination address. The switch will always forward traffic to the specified device
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clear fdb
Restrictions through this port. all − Clears all dynamic entries to the switch’s forwarding database.
Only administrator-level users can issue this command.
Example usage:
To clear all FDB dynamic entries:
DES-3550:4#clear fdb all
Command: clear fdb all
Success.
DES-3550:4#
show multicast_fdb
Purpose
Syntax
Description
Parameters
Used to display the contents of the switch’s multicast forwarding database. show mulitcast_fdb [vlan <vlan_name 32> | mac_address
<macaddr>]
This command is used to display the current contents of the switch’s multicast MAC address forwarding database.
<vlan_name 32> resides.
<macaddr>
− The name of the VLAN on which the MAC address
− The MAC address that is present in the forwarding database table.
Restrictions None.
Example usage:
To display multicast MAC address table:
DES-3550:4#show multicast_fdb vlan default
Command: show multicast_fdb vlan default
VLAN Name : default
MAC Address : 01-00-5E-00-00-00
Egress Ports : 1-5
Mode : Static
Total Entries : 1
DES-3550:4#
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show fdb
Purpose Used to display the current unicast MAC address forwarding database.
Syntax
Description
Parameters
Restrictions show fdb {port <port> | vlan <vlan_name 32> | mac_address
<macaddr> | static | aging_time}
This command will display the current contents of the switch’s forwarding database.
<port> − The port number corresponding to the MAC destination address. The switch will always forward traffic to the specified device through this port.
<vlan_name 32> − The name of the VLAN on which the MAC address resides.
<macaddr> − The MAC address that is present in the forwarding database table. static − Displays the static MAC address entries. aging_time − Displays the aging time for the MAC address forwarding database.
None.
Example usage:
To display unicast MAC address table:
DES-3550:4#show fdb
Command: show fdb
Unicast MAC Address Aging Time = 300
VID VLAN Name MAC Address Port Type
---- ---------------- ----------------- ------ ----------------
1 default 00-00-39-34-66-9A 10 Dynamic
1 default 00-00-51-43-70-00 10 Dynamic
1 default 00-00-5E-00-01-01 10 Dynamic
1 default 00-00-74-60-72-2D 10 Dynamic
1 default 00-00-81-05-00-80 10 Dynamic
1 default 00-00-81-05-02-00 10 Dynamic
1 default 00-00-81-48-70-01 10 Dynamic
1 default 00-00-E2-4F-57-03 10 Dynamic
1 default 00-00-E2-61-53-18 10 Dynamic
1 default 00-00-E2-6B-BC-F6 10 Dynamic
1 default 00-00-E2-7F-6B-53 10 Dynamic
1 default 00-00-E2-82-7D-90 10 Dynamic
1 default 00-00-F8-7C-1C-29 10 Dynamic
1 default 00-01-02-03-04-00 CPU Self
1 default 00-01-02-03-04-05 10 Dynamic
1 default 00-01-30-10-2C-C7 10 Dynamic
1 default 00-01-30-FA-5F-00 10 Dynamic
1 default 00-02-3F-63-DD-68 10 Dynamic
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config multicast port_filtering_mode
Purpose Used to configure the multicast packet filtering mode on a port per port basis.
Syntax
Description
Parameters
Restrictions config multicast port_filtering_mode [<portlist> | all]
[forward_all_groups | forward_unregistered_groups | filter_unregistered_groups]
This command will configure the multicast packet filtering mode for specified ports on the switch.
<portlist> Specifies a port or range of ports to view.
[forward_all_groups | forward_unregistered_groups | filter_unregistered_groups] – The user may set the filtering mode to any of these three options
Only administrator-level users can issue this command.
Example usage:
To configure the multicast filtering mode to forward all groups on ports 1 through 4.
DES-3550:4#config multicast port_filtering_mode 1-4 forward_all_groups
Command: config multicast port_filtering_mode 1-4 forward_all_groups
Success.
DES-3550:4#
show multicast port_filtering_mode
Purpose Used to show the multicast packet filtering mode on a port per port basis.
Syntax
Description
Parameters
Restrictions show multicast port_filtering_mode {<portlist>}
This command will display the current multicast packet filtering mode for specified ports on the switch.
<portlist> Specifies a port or range of ports to view.
None.
Example usage:
To view the multicast port filtering mode for all ports:
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DES-3550:4#show multicast port_filtering_mode
Command: show multicast port_filtering_mode
Port Multicast Filter Mode
------ ---------------------------
1 forward_unregistered_groups
2 forward_unregistered_groups
3 forward_unregistered_groups
4 forward_unregistered_groups
5 forward_unregistered_groups
6 forward_unregistered_groups
7 forward_unregistered_groups
8 forward_unregistered_groups
9 forward_unregistered_groups
10 forward_unregistered_groups
11 forward_unregistered_groups
12 forward_unregistered_groups
13 forward_unregistered_groups
14 forward_unregistered_groups
15 forward_unregistered_groups
16 forward_unregistered_groups
17 forward_unregistered_groups
18 forward_unregistered_groups
19 forward_unregistered_groups
20 forward_unregistered_groups
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